This invention relates generally to vehicle vibration diagnostics and, more particularly, to a system and method for measuring and evaluating torsional vibration in a vehicle driveline.
Driveline torsional vibration problems are a significant source of premature driveline component failures as well as customer noise and vibration complaints, especially in heavy duty trucks. Damaged driveline components are frequently replaced in the field without addressing the root cause of the failure, only to result in a similar failure in the future. Noise and vibration problems are routinely addressed by swapping out driveline components until the problem is seemingly resolved, even in instances when the problem may not even be driveline related. Both situations yield high warranty costs for the component supplier and OEM, and increase the fleet owner's truck down time.
To eliminate this prevalent "trial and error" approach to truck driveline troubleshooting, the driveline vibration analyzer (DVA) of the present invention was developed to quantitatively measure and evaluate driveline torsional vibration. To accomplish this, the DVA measures cyclic speed variations in rotating driveline components and correlates the torsional vibration amplitude to the rotational order of the driveshaft. These speed variations are converted to displacement and acceleration information and separated according to the harmonic order of the driveshaft in order to measure the driveline response to engine and universal joint torsional excitations. Using preselected or calculated orders of interest, the magnitudes of the sensed vibrations in terms of acceleration are compared with predetermined thresholds to aid a test technician in identifying potential vibration problems, determining the source of any problems encountered and selecting a proper remedy for each problem.
The DVA was designed to function as both a torsional vibration analysis instrument as well as a simple field tool suited for rapid troubleshooting. An experienced DVA operator can perform a complete DVA in less than half a day. Implementing the DVA on a laptop personal computer provides portability and enables use by service technicians in a variety of ways to diagnose and solve torsional vibration problems.
These and other features and advantages of the present analyzer will become apparent upon review of the following disclosure taken in conjunction with the accompanying drawings.